The present invention relates to enclosures in which a corresponding loudspeaker is to be mounted and, more particularly, to enclosures in which loudspeakers for responding to low frequency electrical energization are to be mounted to provide sound in the bass audio range.
As is well known, direct radiator loudspeakers, in the absence of any baffling therearound, act as an acoustic dipole because the acoustic energy waves generated from one side of the speaker are in phases opposite to those of the acoustic energy waves generated from the opposite side of the speaker. A considerable efficiency results if the loudspeaker is mounted in a baffle arrangement as the sound reflected from the baffle reinforces the sound radiated outward by the loudspeaker. This is especially true for sounds which have wavelengths greater than the circumference of the loudspeaker, as such sound radiates fairly uniformly in all directions, the improvement assuming that the baffling extends for a distance from the speaker substantially larger than the wavelengths of those sounds.
As a practical matter, a baffle of adequate size for these purposes is approximated by the use of a sufficiently large enclosure in which the loudspeaker is mounted. A sufficient baffle surface will typically lead to a relatively large volume enclosure. Such enclosures typically contain several speakers for various frequency ranges typically requiring some isolation arrangement therein. Often, the enclosure also has a port provided therein to reduce loading on the back of the loudspeaker and reduce distortion for a given power while permitting a smaller enclosure with an improved output over some frequency ranges.
The various resulting structures are subject to developing resonances between the various structural members, and between them and the low frequency loudspeaker used therein. Often, the isolation between the speakers in the multiple loudspeaker enclosure is inadequate, leading to output losses. Thus, there is a desire to provide for a loudspeaker enclosure less subject to such resonances and to any other sources which would affect the fidelity of the reproduced sound while providing an enhanced performance in the bass audio range.